Isosteric analogs of the useful anticancer drugs adriamycin and dunorubicin are being synthesized in which the quinone carbonyls are replaced by N-oxide and by S-oxide funtions. These analogs will be the first with alterations in the carbon skeleton of the tetracycline aglycone. The quinone is a key site of biological action, and the expected alterations in the redox properties of the anthracycline molecule may lead to a separation of the antitumor and toxic effects. Work during the first 7 months has led to construction of tetracyclic aglycone intermediate containing the desired nitrogens in the C ring.